1. Field of the Invention
This invention relates to detection and characterization of SiCOH based dielectric materials during device fabrication, and particularly to the use of chromatography as a means for the detection and characterization.
2. Description of Background
SiCOH low k and ultra low k dielectric materials, also collectively referred to as carbon doped oxide materials or organosilicate glass (OSG), have been implemented in microelectronic devices as low permittivity materials to reduce delay in circuit speed due to capacitance effects. The detection and characterization (e.g., for determining process end point) of SiCOH during processing is critical to speed and reliability performance of the semiconductor devices that are fabricated using this material. The detection and characterization of SiCOH, however, is difficult and non-trivial due to the chemical and structural similarity between SiCOH based dielectrics and more traditional oxide materials such as silicon oxides, fluorinated oxides, silicon nitrides, and the like. In addition, the resolution of conventional characterization techniques such as FTIR, XPS, EDX, and SIMS is not enough to differentiate the subtle chemical and structural changes among the different SiCOH materials. In fact, the detection or endpoint techniques currently available are generally not applicable to device fabrication processes such as chemical mechanical polishing (CMP) or wet strip.
Accordingly, there is a need for improved detection and characterization processes especially as it relates to endpoint detection in CMP and wet strip processes.